1. Field of the Invention
The present invention relates to a display characteristics recognition apparatus for determining display characteristics of a display unit, a display characteristics recognition program storage medium storing a display characteristics recognition program which causes a computer system to operate as such a display characteristics recognition apparatus, a computer system operative as such a display characteristics recognition apparatus, a display characteristics adjusting apparatus for adjusting display characteristics of the display unit, a display characteristics adjusting program storage medium storing a display characteristics adjusting program which causes a computer system to operate as such a display characteristics adjusting apparatus, and a computer system operative as such a display characteristics adjusting apparatus.
2. Description of the Related Art
Recently, in view of the fact that a high performance personal computer comes into wide use and the cost of image input and output units, such as a scanner and a color printer, is decreased, there is increased an opportunity that a color image is dealt with in the form of a home use as well as a business use. As an opportunity of processing a color image for a home use is increased, a problem of a color reproduction quality arises. Specifically, there is associated with such a problem that it is difficult to reproduce a color of an image on the same basis among images such as an original image, a display image on a display, and a print image of a printer. The reason why it is so is that different color input and output units such as a display unit, a printer and a scanner are mutually different in their color developing mechanism and color characteristics of color reproduction areas and the like.
As a technology of adjusting a color in appearance for those different color input and output units, there is known a color management system (CMS). The use of the CMS makes it possible to establish a matching of a color in appearance between an image read through a scanner and an image displayed on a display, and also establish a matching of a color in appearance between an image formed through printing by a printer and an image read through a scanner or an image displayed on a display. Thus, the use of the CMS makes it possible to establish a system in which a user does not feel that something is wrong with an image.
Today, as in ICM 1.0(Image Color Matching) of Windows 95 and Color Sync 2.0 of Macintosh, which are registered trade mark, the CMS is incorporated in the operating system (OS) level. An offer of a predetermined type of device profile used in ICM 1.0 or Color Sync 2.0 to a user by a maker of color input and output units makes it possible that the user obtains an image with which the user does not feel something is wrong, even between images of different devices, for example, a displayed image on a display and a printed image by a printer. The device profile of ICM 1.0 and Color Sync 2.0 is based on the ICC (International Color Consortium) profile advocated by the ICC. Consequently, an offer of the device profile according to the specification of the ICC by a maker of color input and output units makes it possible that both the users of the Windows environment and the Macintosh environment obtain an image with which both the users do not feel something is wrong, even between images of different devices. Thus, it is possible to use various color input and output units without something wrong with a color in appearance. Hereinafter, there will be described a case where the CMS is used for an output unit.
Currently, in the event that the CMS is used in a computer environment, it is general that color display characteristics of an output unit is grasped, and an ICC profile including information indicative of the color display characteristics is adopted.
FIG. 1 is a schematic diagram of an ICC profile.
In the ICC profile, all the necessary data are described by tags. The ICC profile is divided into three parts of a profile header 1 for storing information as to the profile per se such as a file size and a making out date, information indicative of kinds of objective machines (output units), a tagged element data 2 storing information indicative of color display characteristics of an output unit, and a tag table 3 indicative of stored information and storage address of the stored information in the tagged element data 2. The profile header 1 is a fixed length of data. The tagged element data 2 is a variable length of data. The tag table 3 is a variable length of data of (4+12n) bytes including data 3a representative of the number of tags (n) stored in the tagged element data 2, and data 3b, 3c and 3d representative of an identifier, a storage address, a size on each of n pieces of tag, respectively, each of the data 3b, 3c and 3d consisting of 4 bytes.
In the tagged element data 2, a CIEXYZ value of white is stored, as standard white information of the output unit, in wtpt tag with a standardized value in which D50 is adopted as a standard light source. As the standard white information of the output unit, there is known a color temperature indicating white in accordance with a blackbody radiation other than the CIEXYZ value of white. Here, the CIEXYZ value of white is stored in the tagged element data 2. It is possible to perform a transformation between the CIEXYZ value of white and the color temperature in accordance with the conventional scheme. In the following explanation, it happens that the CIEXYZ value of white and the color temperature are used without distinction.
In the tagged element data 2, CIEXYZ values of red, green and blue are stored, as information indicative of a range of color capable of reproduction by the output unit, in rXYZ tag, gXYZ tag and bXYZ tag, respectively, with a standardized value in which D50 is adopted as a standard light source.
Further, in the tagged element data 2, input-output characteristics (γ-characteristics) of the output unit of red, green and blue are stored, as information indicative of γ-characteristics, in rTRC tag, gTRC tag and bTRC tag, respectively, and in general, gradation values are stored where a range between an input 0 and the maximum input is divided into n equal parts.
In this manner, it is general that the tagged element data 2 of the ICC profile of the display unit stores seven sorts of information as mentioned above. Those sorts of information are obtained through such a manner that a specific color image data is inputted to a display or the like so that a color image is displayed, and the color is measured through the use of a dedicated measuring apparatus (a color measuring apparatus).
The ICC profiler is provided nowadays from a color equipment maker to a user in conjunction with a product. Since a color equipment is associated with a difference in display due to a difference among types of the equipment per se and a usage environment, the ICC profile provided by a maker does not always have characteristics of the equipment used by the user. For example, in case of a display, it often happens that a difference in color display characteristics occurs owing to a production lot and a user sets up a display state of a display by a regulatory function (contrast, brightness, RGB balance, color temperature setting) so as to meet the user's desire, and thus usually, the display profile provided by a maker is not suitable for a display which is actually used by a user. In other words, in the CMS, it is difficult to implement a fine color matching with another color equipment. In order to implement a fine color matching, there is a need that a display of a user is measured to collect information data for color display characteristics of the display so that the profile is produced in accordance with the collected information data. However, as mentioned above, for a measurement of a display there is a need to prepare a dedicated measuring apparatus. Such a dedicated measuring apparatus is expensive and thus it is generally that a user has no such measuring apparatus. For this reason, generally, a user cannot produce an ICC profile through a determination of display characteristics of a display unit, and cannot regulate the display characteristics of the display unit.